A navigation system performs travel guidance for enabling a user to easily and quickly reach the selected destination. A typical example is a vehicle navigation system where a vehicle is equipped with a navigation function to guide a driver to a destination through a calculated route. Such a navigation system detects the position of the user's vehicle, and reads out map data pertaining to an area at the current vehicle position from a data storage medium. Typically, the navigation system displays a map image on a monitor screen while superimposing thereon a mark representing the location of the user.
FIGS. 1A-1H show an example of overall procedure and screen display involved in the navigation system for a route guidance operation to a destination. FIG. 1A shows an example of locator map screen of the navigation system when the destination is not specified. Typically, the navigation system displays a street on which the vehicle (vehicle position VP) is running on a map image and a name of the street. Other information such as a north pointer NP, a map scale and a current time may also be illustrated on the display screen.
An example of process for specifying a destination in the navigation system by inputting a street name and street number is described. A main menu screen such as shown in FIG. 1B displays menu items including a “Destination” menu for entering the destination. When selecting “Destination”, the navigation system displays a “Find Destination by” screen as shown in FIG. 1C for specifying an input method for selecting the destination. The “Find Destination By” screen lists various methods for selecting the destination including “Address” for specifying an address of the destination, “Intersection” for specifying the names of two streets which intersect with one another, and “Point of Interest (POI)” for selecting the programmed destination based on the name, category or telephone number, and other input methods known in the art.
When the “Address” method is selected in FIG. 1C, the navigation system displays a screen that allows the user to input a street name as shown in FIG. 1D which includes a keyboard for entering a street name. Next, the navigation system displays a screen for entering a street (house) number as shown in FIG. 1E which includes a numeric keyboard. Then, the navigation system shows a screen to confirm the destination in FIG. 1F.
On the confirmation screen, the user can press the “OK to proceed button” to calculate the route for route guidance. In FIG. 1G, the navigation system displays a progress scale during the calculation of the route to the destination. After determining the calculated route to the destination, the navigation system starts the route guidance operation as shown in FIG. 1H.
In entering a street name, the navigation system is able to assist the user to efficiently find the next character by disabling some keys that do not follow the string of characters that have been entered so far. FIG. 2A shows an example of a display that allows the user to enter a street name with use of an alpha-numeric keyboard. In the display shown in FIG. 2A, no character has been entered in the street name input field 71.
The display in FIG. 2B is similar to the display in FIG. 2A except that the user has entered characters “GRA” in the street name input field 71. Some keys on the keyboard 61 have been shaded, which indicates they are disabled. The navigation system determines available keys (characters) by searching candidate street names in a street name database. The disabled keys tell the user which characters are inappropriate for the street name.
When the navigation system narrows the candidate street names or the user presses the list button 63, the navigation system shows a list of relevant candidate street names as shown in FIG. 2C. The user can select a street name from the candidate list 92 by highlighting the street name. In this example, the candidate list 92 includes the street names “GRAM”, “GRAMA”, “GRAMACY DR”, and “GRAMACY ST”. Scroll arrows 91 on the display 77 allow the user to scroll the list to see more candidate street names if any.
Although the method of specifying an address by entering the street name and the street number described above is effective, disabled keys do not have meaningful function other than indicating that they are unavailable. A large space on the screen is wasted by the disabled keys. The enabled (highlighted) keys showing the next characters of the candidate street names may be far apart from one another where many disabled keys exist therebetween.
In such a situation, when operating a remote controller to input a street name, typically, a joystick on the remote controller has to be used. Unlike a touch screen input method where a user can select the highlighted (enabled) keys by touching the finger on the key, an input method using a pointing device such as a joystick is more difficult to accurately and quickly point a cursor on the highlighted keys. The user would have to focus on the entire layout of the keyboard to move the cursor to one of the highlighted keys. Thus, there is a need of a new key arrangement for a navigation system to accurately and quickly select the characters to input an address on the display screen.